PSI - Issue 66

Ramdane Boukellif et al. / Procedia Structural Integrity 66 (2024) 55–70 Ramdane Boukellif et al. / Structural Integrity Procedia 00 (2025) 000 – 000

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were determined separately for each of the cracks (l = 6 mm, crack angle = 15°, friction coefficient of the crack surfaces = 0.01, friction coefficient cylinder/half-plane = 0.025) (Trollé et al. (2013)). A similar path of the branched crack was predicted using our method, see Fig. 10 (a).

Fig. 10. Comparison of the predicted crack branching with literature: (a) crack paths predicted; (b) literature Trollé et al. (2013).

3.2. Phase I.2: Pure RCF / Consideration of residual stresses The residual stresses were modelled by thermal stresses as shown in Fig. 11. Here, the temperature is specified in the model, which results in thermal expansion. Thermal stresses that correspond to residual stresses are generated by restraints against expansion, e.g., fixed clamping.

Fig. 11. Modelling of residual stresses due to thermal stresses, (a) temperature distribution in the model, (b) thermal stresses (residual stresses) (Boukellif et al. (2024)). An inclined initial crack in Table 2 was considered in this study, see Fig. 12(a). Table 2: Parameters used for the prediction of crack path for the inclined initial crack with consideration of residual stresses. Parameters Initial crack length 0.5 mm Friction coefficient (cylinder/half-plane) Contact pressure Friction coefficient (crack surfaces) Residual stress 0.15 1500 MPa 0.15 yes